I would agree with you. They did control for some factors, and that seemed to be the point of the study, but my first reaction to it was it seems like the cont

I would agree with you. They did control for some factors, and that seemed to be the point of the study, but my first reaction to it was it seems like the controls they used seemed insufficent. It is a shame you were being downvoted - I expect that from other places but not from hacker news.